While potent combination antiretroviral therapy “cocktails” have been truly lifesaving for HIV patients – transforming the formerly fatal diagnosis to a manageable chronic condition over the past fifteen years – a new study of more than 80,000 veterans published in JAMA Internal Medicine Online First shows that increased heart disease risk may be an unexpected side effect. University of Vermont Professor of Pathology and Biochemistry Russell Tracy, Ph.D., served as a coauthor on the paper, which reported that HIV infection is associated with a 50 percent higher risk of heart attack beyond the risk associated with recognized cardiovascular risk factors.

When HIV (human immunodeficiency virus) was first identified in the U.S. in the 1970s, and for 20 years thereafter, it was considered a death sentence, because it led to the fatal AIDS (acquired immunodeficiency syndrome). However, successful treatment of the condition has contributed substantially to the longevity of this population, which, according to The Centers for Disease Control and Prevention, totals an estimated one million people in the U.S.

“Many have suspected that while progression to AIDS has been lessened – or in some groups of people, essentially eliminated – a new risk for non-AIDS related chronic diseases has emerged,” says Tracy. The JAMA Internal Medicine study, he adds, utilized data from the largest cohort yet examined in what is known as the “VA Virtual Cohort.”

In order to determine any relationship between HIV and an increased risk of heart attack, Tracy, along with lead study investigator Matthew Freiberg, M.D., M.Sc., of the University of Pittsburgh School of Medicine, senior author Amy Justice, M.D., M.Sc., Ph.D., of the Yale School of Medicine/VA Connecticut Healthcare System, and colleagues analyzed data from 82,459 veterans – both those infected with HIV and those uninfected. The researchers found that there were 871 acute myocardial infarction (AMI or heart attack) events during a follow-up of about 5.9 years, which represented many more on a percentage basis in the HIV-infected group than in the non-infected group, even after adjusting for all standard Framingham risk factors. “This confirms a substantial increased risk due to HIV infection on top of the risk due to traditional risk factors such as blood pressure and cholesterol,” says Tracy, who adds that “the source of the increased risk isn’t known with certainty.”

However, Tracy and other experts in this field do have an idea about the underlying cause. In a different, but related study, titled “Inflammatory and Coagulation Biomarkers and Mortality in Patients with HIV Infection” and published in PLoS Medicine in 2008, he and colleagues demonstrated that chronic, well-controlled HIV infection is associated with a level of inflammation consistent with increased cardiovascular disease risk.

“Despite our best medications, and since inflammation is known to be an important participant in atherosclerosis and heart attacks, this chronic pro-inflammatory state is the leading candidate,” Tracy says.